Normal-dispersion CS₂-filled silica fiber with broadband single-polarization property

The CS2-filled silica fiber with two air holes in the cladding can offer high nonlinearity, high birefringence and normal group velocity dispersion (GVD) profiles for both two orthogonally polarized fundamental modes (FMs) by an appropriate choice of the fiber parameters. Furthermore, the highly birefringent CS2-filled fiber assisted by two subwavelength-diameter gold wires can exhibit broadband single-polarization (SP) property because that, only the y-polarized FM guided in the CS2-core can couple to the fundamental surface plasmon polariton (SPP) modes with the field vectors along the radial direction, and then has a much larger losses than the x-polarized FM in the wavelength region beyond 1500 nm.

The numerical results show that when the 25-kW 0.1-ps pulse at 1920 nm is coupled into the 0.035-m fiber and linearly polarized along the fast axis, the output pulse exhibits over one-octave supercontinuum (SC) spectrum linearly polarized in the fast axis, and can maintain a linear polarization state across the whole SC spectrum even though the input polarization angle increases to 15° from the fast axis.